In the dryer section, the remaining moisture is removed from paper web by evaporation.

In the calender, the paper is calendered to yield machine-finished paper.

The finished paper web is wound onto a drum (steel core).

Figure 1: Paper manufacturing flowchart

In Central Europe, newsprint is mainly made from waste paper, the proportion in German paper factories being around 60%, and often 90 - 100%. The printing inks are removed from the waste paper by the deinking process.

Paper produced in Scandinavian countries and Canada, where wood abounds, consists of a mixture of fresh fibers from mechanical and chemical pulp.

As a result of new research, the previous manufacturing processes using environmentally unfriendly sulfates, sulfites or chlorine are being abandoned in favor of formic acid, and lower quality starting materials, such as hemp or straw, may be processed instead of wood.

Quality / Duration of storage

Newsprint is a machine-finished printing paper, predominantly for web offset printing. Its basis weight is 40 - 56 g/m². Since damage to the rolls of paper leads to considerable losses, the demands made of transport and storage of such rolls are high.

Fewer demands are made of newsprint with regard to visual characteristics and printability, because, of all the types of paper, newspapers are the shortest-lived sources of information. To keep the retail price low, they must be inexpensive, which is why the waste paper or mechanical pulp content is high. Thus, newsprint exhibits low strength and tends to yellow quickly, i.e. it has low resistance to ageing.

Newsprint must fulfill the following requirements:

Good printability, i.e. it must absorb printing inks rapidly, which is achieved by the high mechanical pulp content.

Good pressroom runnability, i.e. it must be tear-resistant to ensure successful passage through the fast-running rotary machines.

Sufficient opacity, i.e. the print on the reverse must not show through.

Good recyclability, in particular in relation to the deinking process.

Optimum water content of 7%: if paper is too dry, dust develops during printing as a result of "picking" (removal of particles from the surface of the paper web).

Good dimensional stability, i.e. the dimensions (longitudinal and transverse extension) must remain constant during printing. This is influenced by the water content of 6 - 8%.

Intended use

A distinction may be drawn between five groups, according to principal intended use:

Printing and publication paper (graphic paper): such paper is used in the production of newspapers, magazines, catalogs, books, calendars, telephone directories, timetables and address books, newsprint, magazine paper, bible paper, illustration and book printing paper.

Paper and paperboard for industrial and special purposes: filter paper, photographic paper, drawing cardboard, cigarette paper, paperboard for school purposes, album cardboard.

Newsprint, which belongs to the first group, is used for daily and weekly newspapers, magazines, catalogs, newspaper supplements, direct mail items and for advertising flyers. It is processed by both the offset and letterpress methods.

Countries of origin

This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.

Newsprint is transported in rolls up to 300 cm wide and with total weight of up to 4.5 t.

The circumferential packaging for the paper rolls wound ultratightly onto paperboard or metal cores is up to 3.5 mm thick and, as a rule, consists of several plies of kraft paper. To provide protection from moisture, a waterproof ply (e.g. of asphalt paper) is often incorporated therein. The circumferential packaging is folded over the ends by approximately 20 cm. The ends of the rolls are protected with corrugated board covers. In many cases, the final kraft paper cover is plastic-coated and stuck to the folded-over circumferential packaging. Core stability is ensured by a wooden or metal plug driven in at each end.

Standard containers
, subject to compliance with limits for water content of goods, packaging and flooring.

Cargo handling

It is imperative that the goods be protected from moisture (rain, snow) during cargo handling, as there is a risk of losses caused by swelling and tearing of individual layers.

Incorrect handling during loading and unloading and storage entails the risk of snagging. As a consequence, the paper layers become unusable over the depth of the snags. They are then fit merely to be torn off (stripped down) and used as waste paper.

Incorrect cargo handling may result in distortion of paper rolls (ovalization). Rolls exhibiting marked ovality can no longer be used for printing and have to be rewound.

Cargo handling of paper rolls should be performed only with special cargo handling gear and forklift trucks with paper roll clamps.

Stowage factor

1.78 m³/t (paper rolls wrapped in 6 layers of packing paper) [1]

Package dimensions are variable, the important factor being that the rolls within one cargo stack must exhibit uniform dimensions, to prevent distortion.

Stowage space requirements

Holds must be swept absolutely clean and smooth, to prevent any possibility of damage to the ends. The goods must be protected from any possible leakage from hydraulic lines. In addition, the holds must be protected against ingress of moisture.

Newsprint must be protected from all moisture, such as rain, snow, condensation water, seawater, extremely high levels of relative humidity or damp stacking surfaces.

As paper is mainly made from vegetable fibers, it is hygroscopic and has a tendency to swell. Improper storage or care of the cargo may result in dimensional changes, distortion and reduced strength (tearing).

Depending on the type of paper, the water content should be between 6 and 10%. This value remains constant under the storage climate conditions favorable for these materials, i.e. 20°C ± 5°C and a relative humidity of 60 - 70%. The sorption behavior of the paper depends on various factors, e.g. fiber type, freeness, bleaching, sizing, wood content etc..

Figure 4

In [4], the water content at 65% relative humidity of papers with different stock compositions is stated as follows:

Paper grade

Stock composition

Water content of the paper in %

Limit values

Average values

Standard 1

rags

5.4 - 7.5

6.6

Standard 2

rags

5.4 - 7.5

6.6

Standard 3

rags and chemical pulp

5.4 - 7.8

6.8

Standard 4

chemical pulp

5.2 - 10.3

7.0

Standard 5

wood-containing

6.1 - 9.0

8.0

Standard 6

wood-containing

6.8 - 10.0

8.4

True Manilla paper

Manilla

8.4 - 10.0

9.1

Newsprint

high wood content

8.3 - 10.3

9.3

The paper must be protected from sweat by covering the uppermost layer with mats, jute coverings or paper.

Stop cargo handling operations during precipitation and close the holds. Wetting damage may also arise as a result of wet set-down surfaces on the wharf, during storage or in the hold/container as a result of excessively damp wooden dunnage (max. water content 15%) or unsealed weather deck hatch covers. Swelling caused by wetting may lead to a > 50% increase in volume, resulting in swelling and bursting of the outer layers to a considerable depth and rendering several hundred layers of paper unusable.

Cargo sweat is particularly likely to occur during voyages from cold to hot climates or during unloading in tropical ports if the goods were not sufficiently warmed up during the voyage and were exposed to the hot ambient air upon opening of the hatch covers or container doors.

Paper rolls must not be stowed in a hold with other goods which release moisture.

Recommended ventilation conditions: air exchange rate: 6 changes/hour (airing), if the dew point of the external air is lower than the dew point of the hold air.

On voyages from cold to hot climates (Scandinavian ports, Continental ports - tropical unloading ports in Africa, Asia), every possible opportunity for warming the paper must be used to avoid cargo sweat.

Soiling damage is caused by dirty set-down surfaces during precarriage, storage, on the wharf and in the hold/container, by soiled hold or container walls and residues from earlier cargoes on the floor, walls, spar ceilings, underdeck beams or hatch cover girders.

Paper rolls are very sensitive to mechanical influences such as pressure, impact and friction. The risk of damage is greatest during cargo handling.

Figure 5

The following types of damage occur:

Distortion: generally in the form of ovalization of the rolls, arising as a result of excessive stack pressure where rolls are stowed horizontally, since forces are borne solely by the linear bearing surface. In the case of newsprint, damage to the inner core results in interruptions in production or in problems during handling, as the rolls can no longer be lifted correctly. Slight distortion of the core may be remedied. Very oval paper rolls are no longer suitable for printing and are rejected by the receiver, thereby generally entailing total loss, or they have to be rewound, entailing rewinding costs and wasted time.

Figure 6

Telescoping of the paper rolls is caused by pneumatic cargo handling equipment, the rolls being extended in the manner of a telescope, which always results in total loss of the rolls.

Indentations occur both in the roll sides when the rolls are stowed horizontally and in the end faces when they are stowed vertically and are generally caused by residual dirt from earlier cargoes, uneven set-down surfaces and being pressed against structural parts of the means of transport, and also by cargo securing materials.

Edge damage arises when laying down vertical rolls or standing up horizontal rolls, by stowing rolls of different diameters on top of one another or if overhanging roll ends are not adequately supported and by shocks or impacts sustained during cargo handling.

Tear damage: snagged layers result in considerable paper losses, as the rolls become unusable to the depth of the snag. A cut only 2.5 cm deep may result in the loss of as many as 300 layers of paper (then suitable only for use as waste paper).

Figure 7

Rolls must not rub against (chafe) each other or other items; points at risk must be padded with paper bags and air cushions or the like.